An example of a drill bit used for drilling earth bore holes for the exploration and production of oil and gas and the like is a roller cone rock bit. This type of bit employs a multiplicity of rolling cone cutters, also known as rotary cone cutters, rotatably mounted on bearing pins extending from arms of the bit. The cutters are mounted on pins that extend downwardly and inwardly with respect to an axis through the bit axis so that conical sides of the cutters tend to roll on the bottom of a bore hole and contact an earth formation. A number of insert bits or compacts are disposed in the rolling cone cutters to drill the formations at the bottom of the bore hole. These insert bits tend to wear in those areas that engage the bottom and peripheral wall of the bore hole during the drilling operation.
Each insert bit may include a superhard abrasive material bonded to a stud. Abrasive materials such as synthetic or natural diamond, cubic boron nitride, and wurtzite boron nitride are bonded to the stud to increase wear resistance of the insert bit. The abrasive material is often referred to as polycrystalline diamond, PDC, or sintered diamond. The stud may be comprised of a substrate material such as tungsten carbide. One of the factors limiting the wear resistance of the insert bit is the strength of the bond between the polycrystalline diamond and the stud. A weak bond results in decreased wear resistance and premature insert bit failure.